Large telephone switches found in central offices are connected to trunk and distribution wires through terminal blocks. The terminal blocks are supported on a main distribution frame located adjacent to the switch. The frame includes a number of metal traverse arms. Flanges are welded to the ends of some of the arms, and the terminal blocks are bolted to the flanges.
Newer switches are not necessarily compatible with terminal blocks used with older switches. When a central office is converted to a new switch, new terminal blocks must be wired in to replace the old.
Such conversions can take several weeks. During the conversion period, both old and new terminal blocks must be concurrently wired.
Kits are commercially available which extend the frame arms, so that both new and old blocks can be simultaneously accommodated on the frame during the conversion period. These kits include a bar which is clamped to the bottom of a frame by U bolts. The bars are drilled to accept a separate flange for bolting the new terminal block. During installation, the assembly of a number of small parts is required. This is difficult, at best, in an already cramped environment.
It would therefore be desirable to provide a unitary telephone main distribution frame arm extender for mounting terminal blocks.